Exhaust Link Pipes?
Exhaust Link Pipes?
(OP)
Hi, just wondering if anyone has any opinion or info on this... I am currently building a race bike and due to limited budget I am going to be using the stock exhaust system. Firing order is 1-2-4-3 and the downpipes are linked 1 to 4, and 2 to 3. The collector is a 4-2-1. The cam profiles (stock) are quite short and so I am going to tune the bike for maximum power in quite a narrow rev range.
My question is this - can I gain any power by removing the link pipes?? Are the link pipes there to help power throughout the whole range?? If this is the case then surely removing the link pipes will help the top end...
Ideally speaking I would like to make power over a wider range but unfortunately I can't invest much more money into the bike and my only option is to modify what's there to suit.
Thanks in advance,
D.
My question is this - can I gain any power by removing the link pipes?? Are the link pipes there to help power throughout the whole range?? If this is the case then surely removing the link pipes will help the top end...
Ideally speaking I would like to make power over a wider range but unfortunately I can't invest much more money into the bike and my only option is to modify what's there to suit.
Thanks in advance,
D.





RE: Exhaust Link Pipes?
I t will be great to get more motorcyclist there...
RE: Exhaust Link Pipes?
Mike Halloran
Pembroke Pines, FL, USA
RE: Exhaust Link Pipes?
Mike, if you had read by post properly you would see that I am financially restricted to the amount of development I can do on the engine. My question was about link pipes, not whether the bike will be competitive...
RE: Exhaust Link Pipes?
For reference, on any given day, starting around the middle of the previous century, and continuing through today, there have almost always been some proponents of ADDING a crossover or link pipe between the branches of a hIgH PeRfOrMaNcE exhaust system. A few have even had their names beside a drag racing or Bonneville record or two. "Scientific" explanations of what crossovers do, and why, vary a bit. The one I find easiest to believe is basically 2 mufflers flow more than 1. Methods of determining "the" location and size of the crossover have been "interesting," too. For a while it was popular to paint the (single wall) pipe and look for a transition between charred and non-charred paint. Allegedly just as useful for setting collector length or installing a crossover.
For sure my biggest tuning successes and failures have involved carburetor jets and needles. The butt dyno reports HP and torque improvements (and crushing losses) of over 100%.
RE: Exhaust Link Pipes?
Regards,
MB
RE: Exhaust Link Pipes?
MB, I think you're right, they're best left alone - the documentation I found was pretty basic but explained the difference between H and X link (or balance) pipes and the effects each had on performance. It seems the X type is fair better but it's actually more like a collector than anything else. I used to ride a VTR1000 and that had the same set up, both exhaust pipes coming together and then splitting again to seperate cans. The bike in this case is a ZXR400.
I'll leave it as is anyway, but I still want to get a more meaty breakdown of why it works better and how to determine where the X 'join' is. It would be interesting to do a Matlab (or similar) simulation of an exhaust system...
RE: Exhaust Link Pipes?
Regards,
Michael
RE: Exhaust Link Pipes?
Cheers,
Dave
RE: Exhaust Link Pipes?
Regards,
Michael
RE: Exhaust Link Pipes?
"The engineers that designed the exhaust system have alot more equipment/time/knowledge to design the exhaust for its specific engine operation."
which is true as far as it goes, BUT the "specific engine operation" that the original engineers intend is likely very far removed from the specific engine operation "collinsda" intends.
Now regarding those pipes, Collins:
It is also quite likely that those crossover pipes are present to improve noise rather than performance. Even if intended to improve performance, it's unlikely they would improve performance in the peak rpm range that you intend to operate in, so I wouldn't hesitate to remove them.
But here's something you can do: cut the pipes and block them with e.g. a flat plate, and test the bike with the pipes blocked. If performance is worse, remove the plate and repair the cut. If better...
RE: Exhaust Link Pipes?
Cheers,
Dave.
PS: thanks for the pipe dimensions Michael!